Random Freezes, stops working completely

Ferimer

Distinguished
Overnight I would leave my computer on and it would completely stop up and freeze, wasnt doing anything computer was just on, when i would wake up in the morning it would be frozen (last image on screen) and i had 0 response from keyboard and mouse had to do a hard reset on the computer. Just about 10 minutes ago I was playing a game and it did it then also. Today I took everything out, cleaned the inside, got rid of all the dust build up in the computer and underneath where the fans are, I did that before the Freeze happened with the game. I also replaced the Thermal paste that was on my EVO Fan as it was Stock paste.